D. c. voltage relay



C. THUMIM D. C. VOLTAGE RELAY Aug. 28, 1956 2 Shee ts-Sheet 1 IN V EN TOR. c442 7110/14/41 Filed July 11, 1952 C. THUMIM D. C. VOLTAGE RELAY Aug. 28, 1956 2 Sheets-Sheet 2 Filed July 11, 1952 6 a m Z W w F z W Z a z W m 4 1 M w m a w 5 a w 6 2 i W 6 4, 3 W m K 3 M 20. L I [I [IA 9 5 3 9 2 a 2 W W /\J| J 75 a 2 1- z 4 m I I N V EN TOR.

6'46; 7Z/uM/M M BY 38 4/ United States Patent D. C. VOLTAGE RELAY Carl Thumim, Yeadon, Pa., assignor to l-T-E Circuit Breaker Company, Philadelphia, Pa.

Application July 11, 1952, Serial No. 298,320 12 Claims. (Cl. 317- 157) This invention relates to a direct current voltage relay of particularly rugged construction and suitable for service where it must necessarily be sensitive to a predetermined pickup voltage and to a predetermined drop-out voltage, and yet be relatively insensitive to vibration and shock.

The primary object of this invention is to provide a sensitive voltage relay constructed to be relatively insensitive to vibration and shock, and that shall have certain features of design that shall permit the relay to be adjusted to be sensitively responsive to a desired predetermined voltage for operating the relay to closed position, and that shall be sensitively responsive to a predetermined lower voltage for operating the relay to open position. The operation of the relay is utilized to operate a set of switches to control the circuits of external devices.

A feature of this invention is the provision of a motor magnet in which a large change of energizing voltage on the relay, during an energized condition of the relay, will be attended by only a relatively small motion of the movable armature of the motor, so that a substantial part of the stored energy in the movable motor armature may be utilized mechanically to open the relay when the energizing voltage drops to a predetermined value. I

Another feature of the invention is the provision of a latching system for the relay which remains unaffected by normal vibration or shock so long as the operating voltage of the energizing circuit remains above a predetermined value.

Another feature of the invention is the provision of a latching system for the relay which is arranged to be quickly operated from normal latching position to released position by an impact force when the main circuit voltage drops to or below a predetermined value at which the opening of the relay is desired.

A still further object of my invention is the provision of a direct current relay in which a voltage measuring network controls the energization of a closing solenoid and latch member.

A further object of my invention is the provision of a voltage-responsive voltage measuring device which includes an electromagnetic motor having a pivotally supported armature and contact assembly which .is insensitive to vibrational or shock forces.

Another object of my invention is a voltage measuring device for a direct current relay having contact-armature structure which is mounted in such a manner as to prevent the development of a mechanical force couple.

Another object of my invention is the provision of a shock latch for a direct current relay operating arm which is rendered ineffective by a voltage measuring network controlled auxiliary relay.

Another object of my invention is to provide a voltage measuring network having calibration means for contact pressure to adjust the drop out value of a direct current voltage relay.

Still a further object of my invention is to provide a voltage measuring device in which the armature and contacts assembly are pivoted about a common axis to eliminate undesirable effects of shock and vibrational forces.

Still another object of my invention is to provide a corn mon pivotal axis for an electromagnetic motor armature and contact assembly to insure no wipe between contacts to thereby avoid wiping friction and improve sensitivity.

Another object of my invention is to provide a common pivotal axis for a motor armature and contact assembly so that both rotational and rectilinear shock forces will not result in contact disengagement.

Still another object of my invention is to provide a substantially frictionless bearing for a pivoted contact assembly to eliminate friction losses and permit exact value of contact pressure springs to be effective during both rising and falling values of voltage.

Still another object of my invention is to provide a direct current voltage relay with a voltage measuring network which on lowering of the voltage to drop out value will permit the free movement of the motor armature to open the holding latch with impact.

The general principles underlying the operation of the relay and the various features thereof are more fully described in connection with the accompanying drawings in which:

Figure 1 is a schematic mechanical and electrical diagram of the operating elements and functions of the relay;

Figure 2 is a graph showing the relationship between the operating force on the sensitive motor relay element and the motion of the armature, and the correlated relationship to the adjustable springs by means of which the various operating points of the relay are established;

Figure 3 is a plan view showing the mechanical relationship between the axis of rotation of the armature of the motor relay and pivotal axis of a pair of contacts controlled thereby so the axis will be common for the armature and the contacts to provide minimum contact wipe in order to eliminate friction cause-d thereby and thus to make the relay more sensitively responsive to the action of the forces involved, especially during the opening stroke;

Figure 4 is a schematic end view of the armature and contact engagement to show the alignment of their axis of angular movement.

Figure 1 shows the various elements and components that comprise and enter into the operation of the direct current voltage relay 10. The relay 10 as a whole comprises a main set of contacts shown as a group of normally opened switch contacts 11 and normally closed switch contacts 12, that are suitably supported on an operating arm 13, which is in turn supported on, secured to and controlled by a pivoted closing lever 14 that is arranged to be actuated by a closing magnet core 15 when magnet 15a is energized by a voltage of suitable value, which, for the purpose of the present illustration, will be taken as of rated voltage of the supply circuit 16.

During conditions of normal voltage on the supply circuit 16, it is desired that the voltage relay be operated to close the switch contacts 11 and to open the switch contacts 12, and to maintain those switch contacts in those positions so long as the voltage on the supply circuit 16 does not drop below a predetermined value.

For the purpose of the present illustration, the drop-out value of the relay will be taken to be 65% of normal rated voltage of the supply circuit 16.

Since the relay 10 is primarily intended for service where it may be subjected to substantial and practically continuous vibration, and quite frequently to sudden shocks, it is necessary that the relay remain in its energized closed position to maintain the switch contacts 11 and 12 in their desired conditions so long as the supply circuit 16 is kept at a voltage above 65 of rated voltage, notwithstanding any vibration or shock.

er to combine the ruggedness and insensibility to s lih the feature of sensitivity in response to the vo -I ge of the supply circuit 16, a mechanical latch 17 is e led to latch the operating lever 14 in closed position when the voltage conditions on the supply circuit are proper, and a motor relay 18 with substantially instrument sensitivity is employed to provide the sensitive control of the l ch in accordance with the voltage on the supply circuit 6. The motor relay 18 comprises a magnetizable core 19 and an energizing coil 20.

.he core 19 is provided with two oppositely disposed pole pieces 21 and 22, having faces arcuately shaped about a transverse central axis 23.

The motor relay 28 further comprises an armature 24 of inagnetizable material supported for normal movement about the transverse axis 23 and has its end faces 25 and 26 arcuately shaped about that axis as a center and properly dimensioned to permit the armature to move freely between the pole pieces of the core 19 with .a relatively small air gap.

The armature 24- of the motor relay 18 has several functions. One function is to establish a circuit that will lead to the energization of the main closing coil 15, and that will provide a locking circuit for the energizing coil 26 of the motor relay 18. To establish that circuit, the motor armature 24 angularly moves a bridging contact 28 into engagement with two pivotally supported floating contacts 29 and 38. After the motor armature 25 has moved contact 2-3 through an angle sufiiciently to bridge those two contacts 29 and 30, and assuming that the voltage of the supply circuit 16 is at least 90% of normal rated voltage, the armature 25 will continue its clockwise angular movement to a position at which the armature the pole faces will overlap approximately 50%. At that point, the armature will be stopped by a tail plate 31 on the armature, engaging an adjustable stop 32 supported on a stationary part 33 of the supporting frame of the relay.

The two floating contacts 29 and 30 are respectively supported on bars 34 and 35, which are shown pivotally supported at 36 and 37 on stationary portions of the supporting frame, as seen in Figures 1, 3 and 4. The lower ends of the supporting bars 34 and 35 are respectively biased by suitable tension springs 38 and 39, that are respectively anchored at their other ends by adjusting screws 4i and 42 supported on stationary parts of the supporting frame. The extent of adjustment of these two tension springs 38 and 39 will be defined in some detail later.

it this time, attention is directed to the fact that axis of rotation of the armature 25 of the motor relay 1% also constitutes the pivotal axis about which the bars 34 and 35 are supported and mounted to operate. That arrangement is shown and explained in more detail in connection with Figures 3 and 4.

By means of this arrangement of the contact supporting bars 34 and 35 on a pivotal axis 23:: co-axial with the axis of rotation 23 of the armature 25, any rectilinear shock force moving in any direction transverse to the axis 23 would be equally effective above and below the axis 23, and therefore cancelled out in its effect on either the armature or the contact supporting bars 34 and 35. Rotational forces will be effective on both the support bars 35 and 34, and the armature bridging member 28. Hence, the two members will rotate together and the contacts will remain in engagement. Thus, the only force that could be effective on the armature would be the magnetic field force developed between the pole faces of the relay core 19 and the mechanical reaction forces of the several adjusted springs against which the armature is intended to operate.

In order that the control circuit that is set .up by the operation of the motor relay armature 25 by bridging the contacts 29 and 30 may be completely explained and studied at this point, the related electrical circuits of the relay will be traced.

The energizing circuit for the field coil 20 of the motor relay 18 proceeds from the supply circuit 16, through conductor 45, a swamping resistor 46, the operating relay field coil 20, conductor 47, to a contact finger 48 of a pallet switch 4) controlled by the operating lever 14- of the closing magnet. The pallet switch 49 also embodies two finger contacts, an upper contact 51 and a lower contact 52 and a movable conducting plate 53. Plate 53 establishes a circuit from the main contact 48 to the upper finger contact 51 while the main closing magnet core 15 is in its de-energized lowered position, and establishes a circuit from the main contact 48 to the lower finger contact 52 in the energized or raised position of the closing mag net core 15.

The initial circuit of the motor relay coil 20 is thus completed trough the circuit previously traced and through the electrical connection between contact 48 and contact 51 at the pallet switch 49, since finger contact 51 is connected to the ground, which represents the return conductor 16b of the supply circuit 16.

Assuming adequate voltage on the supply circuit 16, the motor relay 13, upon being thus energized, will bridge the contacts 29 and 30 by contact 28 to close the circuit of the operating coil of an auxiliary relay 55. it will be noted that since the bridging arm 28 and contacts 29 and 30 of the contact assembly 34 and 35 are pivoted about a common pivot 23 there will be no wiping action between the contacts. This will therefore eliminate any wiping friction and improves sensitivity.

The circuit to the auxiliary relay 55 may be traced from the supply circuit top bus 16, down through conductor 56, the operating coil of the auxiliary relay 55, conductor 57 to a cut-elf switch 58, down through conductor 59 and through the pivoted contacts 29 and 3t and the bridging contact 28, to the ground or return conductor 16b of the supply circuit.

Auxiliary relay 55 is thereupon energized to close its switch contacts 61 to complete the circuit for the closing solenoid 15a, from main supply 16 down through conductor 56, the switch contact 61 and the closing coil 15a to ground. In addition, as will hereinafter be more fully explained energization of auxiliary relay 55 will render the auxiliary shock latch S inefiective.

The contact switch assembly, including the pivoted contact bars 34 and 35 and their contacts 2) and 39, is thus operated by the motor relay armature 24 to control the energization coil 15, and to establish a holding circuit for the energizing field coil 20 of the motor relay in order to keep the field coil 20 energized when the solenoid 15a raises the operating arm 14 and the pallet switch 49. That is when the existing circuit for field coil 20 through the pallet switch from contact 48 to contact 51 is broken, the contacts 23, 29 and 36 complete a part of a holding circuit for coil 29.

Downward movement of the pallet switch 49 establishes the other part of the holding circuit for the energizing field coil 26 of the motor relay, by electrical connecting switch contact finger 48 to switch contact finger 52 at the pallet switch to complete the establishment of the holding circuit for the field coil 20 of the motor relay; switch over from 51 to 52 is accomplished without breaking circuit through 20 by overlapping design. This is done by moving 53 just long enough to touch contacts 51 and 52 simultaneously during motion of 14.

As heretofore notcd the closing of contacts 28, 29 and 30 will energize the coil 55 of auxiliary relay 55. The movement of the armature of this relay will not only close contacts 61, but will also by link 211 release auxiliary latch 8 from engagement with operating arm 14. Hence upon energization of the closing solenoid 15a by adequate voltage on the supply circuit 16, at least the operating arm 14 will be raised to the closed position. At this time a latch-bearing ring, 64, pivotally mounted at the outer end of operating arm 14, will'b'e moved to the dotted position indicated, immediately above the toe 65 of the latch 17, where the latch bearing roller 64 will be held propped and blocked against downward movement until the latch 17 is moved angularly clockwise out of the downward or return path'of the bearing latch roller 64.

During the upward movement of the operating arm'14,"

a small tip 66 on the upper edge of the arm 14 will engage the spring biased cut-olf switch 58 at the upper terminal point of the path of movement of the latch roller 64, directly above the latch 65. The cut-oil switch 58 opens the circuit of the operating coil of the auxiliary relay 55 which is thereupon returned to its open position by its biasing spring 55a, to open the main switch'contact 61, which in turn opens the energizing circuit of the main closing solenoid 15a.

The upward movement of the operating arm 14 is in a counterclockwise direction about a stationary pivot 68, that is supported on the relay structure. Arm 14 during such counterclockwise movement compresses a compression spring 69 to store energy for subsequent operations for a quick opening return movement of the operating arm 14 when that arm is un-propped and released by the latch 17.

The operation of the latch 17 is suitably controlled in accordance with the voltage at the supply circuit 16 and the consequent clockwise electromagnetic torque developed at the armature 24 of the motor relay, and in accordance with the counter torque set up by the stored stresses in several selectively adjusted springs by means of which the desired operating points of the relay may be predetermined.

The latch 17 is pivoted on a stationary pivot 71 suitably supported on the relay structure, and in the de-energized condition of the relay is biased clockwise to rest its heel 72 against a stationary stop 73, to limit its clockwise movement around the pivot 71.

Two selectively and individually adjustable springs 74 and 75 exert a clockwise bias on the latch for purposes presently to be explained.

As schematically illustrated, the latch 17 is shaped as a bell crank with its lower arm 76 controlled by the armature 24 of the motor relay. The armature 24 embodies an arm 77, having one end of horizontal link 78 pivotally fixed to the upper end thereof. The other end of the link 78 is supported for limited lost motion on a pin 79 secured to the lower end of the lower arm 76 of the latch 17. A slot 81 at the outer end of the horizontal link 78 permits the limited lost motion movement between the pin 79 and the link 78. A tension spring 82 is disposed with one end adjustably anchored on an adjustable bolt 82a on the armature arm 77, and. the other end of the spring 82 is anchored on the pin 79.

When the armature 24 of the'motor relay is energized and angularly moved clockwise, its action on the link 78 and the spring 82 will be such as to move the link 78 and the spring 82 as a unit in a clockwise direction for a short distance sufficient to move the latch 17 counterclockwise to the latching position indicated in dotted lines against bias of springs 74 and 75. Further counterclockwise movement of the latch will be prevented by an arrangement presently to be described, but the link 78, due to the lost motion connection with arm 76 of the latch 17, continues to move in a clockwise direction with the armature 24.

The left-hand end of spring 82 is anchored, however, on the pin 7 at the lower end of the latch arm 76. The spring 82 will therefore be stressed and tensioned through the length of the lost motion movement permitted to the armature 24 and link 78 until the tail piece limit arm 31 on armature 24 and associated with the contact assembly 28, 29 and 30 engages the limit stop 32 previously described.

The manner in which the counterclockwise movement of latch 17 to its latching position is controlled, will now be considered.

The latch embodies a backwardly extending arm 83 which serves as one arm of a balancing linkage and is suitably pinned by pin 83a to one end 84 of a lever 85 that serves as the other arm of the linkage. The lever 85 is pivotally supported on a stationary pivot 86 and the other end 87 of the lever is positioned to engage a limit stop 88, in the clockwise direction of movement of the end of the lever 87.

The function of the stop 88 is to provide a rigid bracing surface for the lever arm 87, in order that the lever may then work back to impress a limit stop action on the latch 17 at the end of the rearwardly extending arm 83 of the latch 17. For that reason, the adjustment of the operating surface of the stop limit 88 is therefore established by a suitable number of non-compressible shims 89, upon final assembly, which are then clamped in position by suitable means to prevent their displacement from operating position. Use of lever 84 provides means to counteract effect of rotational shock on 17 and to provide stop adjustment where it is easily accessible and where it can be protected against stop reaction shock.

A pivoted link and roller assembly 92 is pivoted on the fixed pivot 86 of the lever 85 with a heavy roller 93 disposed to lie on lever 87 to provide a shock absorbing mass which will move upward by the Well known billiard ball efiect from shock transmitted from the main frame to stop 88.

In addition to all these shock absorbers, it is necessary to supply a shock counterbalanced latch 226 to catch pin 83a during rotational and stop reaction shock. The hair pin spring 218 keeps latch 226 properly centered.

Another addition is shock latch 8 which is biased to engage pin 64a and thus keep shock from lever arm 14 counterclockwise when it is in the open position. When, during operation, auxiliary relay 55 is energized, a tie link 211 pulls 8 out of engagement with 64a and permits 15 to move upward due to energization of 15a.

Theoperation of the relay may now be considered. Assumlng normal voltage is restored on the supply circuit 16, the field winding 20 of the motor relay will be energized through the circuit previously traced. The operating arm 14 for the switch contacts will be in lower or open position, as illustrated in Figure l.

The motor field coil 20 is energized and causes armature 24 to move clockwise to tension spring 82, and to then turn latch 17 as a bell-crank to tension spring 74 and 7d. Spring 82 is stronger than spring 74 and 75, which therefore yield first until the latch 17 tilts reaction lever 85 to move lever arm 87 to limit stop position against stop 88. This all occurs before the voltage has reached the level to operate the relay 55 and before the armature 24 is rotated through its full permitted angle.

When the counterclockwise latch movement is stopped by reaction lever 85 at stop 88, the tension spring 82 is then stressed by further movement of relay armature 24 until the floating bridge contact 28 is moved to engage contacts 29 and 30. The circuit to auxiliary relay 55 is then closed, and relay 55 operates to remove latch 8 and to close the circuit to the main lifting magnet coil 15a to operate the main switch contact assembly.

Operating arm 14 is raised to upper position, past the front edge of latch toe 6S and up onto the top of latch 17, where it stays propped until released by operation of the latch 17. Just at the time of elevation of arm 14 to latched position, the tip 66 opens auxiliary contact 58 to ultimately de-energize main operating coil 15a. The switch main operating arm 14 is now held propped by latch 17 and is ready to drop quickly upon movement of the latch from propping position.

While the main operating arm is held in propped position the relay field coil 20 is energized through pallet switch fingers 48 and 52 and through contacts 28, 29 and 30 controlled by armature 24; the armature 24 is held clockwise by electromagnetic force to keep spring 82 stressed.

When the voltage drops to a level where armature 24 moves out of the direct air gap between the core pole pieces 21 and 22, due to the electro-magnetic holding torque being exceeded by the mechanical opening torque of tension spring 82 and contact springs 38 and 39, the magnetic attraction on relay armature 24 diminishes and the armature 24 opens the circuit at the floating switch assembly, between contacts 28, 29 and 3d. The circuit of field coil is thereupon opened and armature 24 is free floating to move quickly. Spring 2 is anchored at one end on pin 79 and held stationary near the left-hand end of slot ill at lower end of arm 76. The other end of spring 8?. is anchored at back end of link 78. Thus when the armature 2d and the back end or" spring 82 are released, the link '73 is propelled to the left-hand side, to strike pin 79 with the right end of slot 81. The impact energy of the blow, due to the energy stored in link 78 and armature 24, plus springs 74 and '75, snap the latch 17 clockwise and unprops the main operating arm 14. This permits the operating arm 14 to turn clockwise due to the energy in the compressed spring 6?.

The interaction of the spring vs. shown in Figure 2 where curve A is the magnetic pull torque exerted by armature 24 at pick up value of voltage.

B is the magnetic pull torque exerted by armature 24 at drop out value of voltage.

C is the torque exerted by springs 74 and 75 until 87 touches 8%.

D is the torque exerted by spring 82 up to the end of the stroke when arm 25 strikes stop 32.

E is the additional torque exerted by contact pressure springs 38 and 39 until stop 32 is butt with bridge 28.

Hence, it can easily be seen that adjustment of tension on 82, 33 and 39 determines the drop out value of the armature 24- and adjustment of '74, 75 and 82 determines the pick up value of armature 2- While I have shown and described my invention as applied to a particular system of connections and as embodying various devices diagrammatically shown, it will be obvious to those skilled in the art that changes and modifications be made without departing from my invention, and I therefore aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What 1 claim as new and desire to secure by Letters Patent of the United States is:

l. A direct current voltage relay for measuring and respondi g to the volta e of a supply circuit and comprising main switch contacts, an operating arm, a biasing means, a closing solenoid, a latch member and a voltage measuring network; operating arrn being operatively connected to switch contacts and constructed to be operable bet. ween open and closed position; said closing solenoid being operativeiy connected to said operating arm, said closing solenoid being constructed to move said operating arm to said closed position responsive to energization of said closing solenoid; said latch member having a release position and a latching position, said latch being constructed to latch said operating arm in said closed position when said operating arm is moved to said closed position; said biasing means being constructed to bias said operating arm to said open position when said latch member is in said release position; said voltage measuring network comprising electromagnetic motor having a core having an energizing winding wound thereon and a pivoted armature; energizing winding being energized by the voltage of said supply circuit, the angular position of said pivoted armat re being determined by the energization of said energizing winding; a pivoted contact assembly and an extension on said pivoted armature; said extension being constructed to carry contacts for cooperation with said pivoted contact assembly; said extension being moved into magnetic forces is engagement with said pivoted contact assembly responsive to rotation of said supply circuit, said solenoid being energized responsive to contact engagement between said pivoted contact assembly and said extension; said latch member being operatively connected to said pivoted armature, rotation of said pivoted armature in a direction to disengage said extension and said pivoted contact assembly being eliective to move said latch member to said release position; means for supporting said pivoted armature and said pivoted contact assembly about a common pivoted axis, vibrational force and shock force being directionally effective in the same direction on both sides of said pivoted axis to thereby prevent development of a mechanical force couple in a direction to rotate said pivoted armature.

2. A direct current voltage relay for measuring and responding to the voltage of a supply circuit and comprising main switch contacts, an operating arm, a biasing means, a closing solenoid, a latch member, a voltage measuring network, an auxiliary latch and an auxiliary relay; said operating arm being operatively connected to said switch contacts and constructed to be operable between an open and closed position; said closing solenoid being operatively connected to said operating arm, said closing solenoid being constructed to move said operating arm to said closed position responsive to energization of said closing solenoid; said latch member having a release position and a latching position; said latch being constructed to latch said operating arm in said closed position when said operating arm is moved to said closed position; said biasing means being constructed to bias said operating arm to said open position when said latch member is in said release position; said voltage measuring network comprising an electromagnetic motor having a core having an energizing winding wound thereon and a pivoted armature; said energizing winding being energized by the voltage of said supply circuit, the angular position of said pivoted armature being determined by the energization of said energizing winding; a pivoted contact assembly and an extension on said pivoted armature; said extension being constructed to carry contacts for cooperation with said pivoted contact assembly; said extension being moved into engagement with said pivoted contact assembly responsive to rotation of said pivoted armature due to a predetermined voltage value of said supply circuit, said auxiliary relay being energized responsive to contact engagement between said pivoted contact assembly and said extension; said solenoid being energized responsive to energization of said auxiliary relay; said latch member being operatively connected to said pivoted armature, rotation of said pivoted armature in a direction to disengage said extension and said pivoted contact assembly being effective to move said latch member to said release position; means for supporting said pivoted armature and said pivoted contact assembly about a common pivoted axis, vibrational force and shock force being directionally effective in the same direction on both sides of said pivotal axis to thereby prevent development of a mechanical force couple in a direction to rotate said pivoted armature; said auxiliary latch being positioned to maintain said operating arm in said open position against shock, said auxiliary latch being constructed to unlatch said operating arm responsive to energization of said auxiliary relay.

3. A direct current voltage relay for measuring and re sponding to the voltage of a supply circuit and comprising main switch contacts, an operating arm, a biasing means, a closing solenoid, a latch member, voltage measuringnetwork, an auxiliary latch and an auxiliary re lay; said operating arm being operatively connected to said switch contacts and constructed to be operable between an open and closed position; said closing solenoid being operatively connected to said operating arm, said closing solenoid being constructed to move said operating arm to said closed position responsive to energiza= tion of said closing solenoid; said latch member having a release position and a latching position; said latch being constructed to latch said op rating arm in said closed position when said operating arm is moved to said closed position; said biasing means being constructed to bias said operating arm to said open position when said latch member is in said release position; said voltage measuring network comprising an electromagnetic motor having a core having an energizing Winding wound thereon and a pivoted armature; said energizing winding being energized by the voltage of said supply circuit, the angular position of said pivoted armature being determined by the energization of said energizing winding; a pivoted contact assembly and an extension on said pivoted armature; said extension being constructed to carry contacts for cooperation with said pivoted contact assembly; said extension being moved into engagement with said pivoted contact assembly responsive to rotation of said pivoted armature due to a predetermined voltage value of said supply circuit, said auxiliary relay being energized responsive to contact engagement between said pivoted contact assembly and said extension; said solenoid being energized responsive to energization of said auxiliary relay; said latch member being operatively connected to said pivoted armature; rotation of said pivoted armature in a direction to disengage said extension and said pivoted contact assembly being effective to move said latch member to said release position; means for supporting said pivoted armature and said pivoted contact assembly about a common pivoted axis, vibrational force and shock force being directionally effective in the same direction on both sides of said pivotal axis to thereby prevent development of a mechanical force couple in a direction to rotate said pivoted armature; said auxiliary latch being positioned to maintain said operating arm in said open position against shock; said auxiliary latch being constructed to unlatch said operating arm responsive to energization of said auxiliary relay; contact pressure springs; said contact springs being positioned to bias said pivoted contact assembly into electrical engagement with said contacts carried by said extension or" said pivoted armature, calibration of said contact pressure springs being eiiiective to adjust the drop out value of said direct current voltage relay; said pivoted contact assembly being pivotally mounted on substantially frictionless bearings to thereby eliminate friction losses and to permit exact adjustment of the drop out value of said direct current voltage relay for both rising and falling values of voltage.

4. A direct current voltage relay for measuring and responding to the voltage of a supply circuit and comprising main switch contacts, an operating arm, a biasing means, a closing solenoid, a latch member, a voltage measuring network, an auxiliary latch and an auxiliary relay; said operating arm being operatively connected to said switch contacts and constructed to be operatively connected to said switch contacts and constructed to be operable between an open and closed position; said closing solenoid being operatively connected to said operating arm, said closing solenoid being constructed to move said operating arm to said closed position responsive to energization of said closing solenoid; said latch member having a release position and a latching position, said latch being constructed to latch said operating arm in said closed position; said biasing means being constructed to bias said operating arm to said open position when said latch member is in said release position; said voltage measuring network comprising an electromagnetic motor having a core having an energizing winding wound thereon and a pivoted armature; said energizing winding being energized by the voltage of said supply circuit, the angular position of said pivoted armature being determined by the energization of said energizing winding; a pivoted contact assembly and an extension on said pivoted armature; said extension being constructed to carry contacts for cooperation with said pivoted contact assembly; said extension being moved into" engagement with said pivoted contact assembly responsive to rotation of said pivoted armature due to a predetermined voltage value of said supply circuit, said auxiliary relay being energized responsive to contact engagement between said pivoted contact assembly and said extension; said solenoid being energized responsive to energization of said auxiliary relay; said latch member being operatively connected to said pivoted armature, rotation of said pivoted armature in a direction to disengage said extension and said pivoted contact assembly being effective to move said latch member to said release position; means for supporting said pivoted armature and said pivoted contact assembly about a common pivoted axis, vibrational force and shock force being directionally effective in the same direction on both sides of said pivotal axis to thereby prevent development of a mechanical force couple in a direction to rotate said pivoted armature; said auxiliary latch being positioned to maintain said operating arm in said open position against shock, said auxiliary latch being constructed to unlatch said operating arm responsive to energization of said auxiliary relay; said common pivotal axis for said pivoted armature and said pivoted contact assembly insuring no wipe between contacts carried by said pivoted armature and contacts carried by said pivoted contact assembly to thereby avoid wiping friction and improve sensitivity; said pivoted contact assembly being pivotally mounted on substantially frictionless bearings to thereby eliminate friction losses and to permit exact adjustment of the drop out value of said direct current voltage relay for both rising and falling values of voltage.

5. A direct current voltage relay for measuring and responding to the voltage of a supply circuit and comprising main switch contacts, an operating arm, a biasing means, a closing solenoid, a latch member, a voltage measuring network, an auxiliary latch and an auxiliary relay; said operating arm being operatively connected to said switch contacts and constructed to be operable between an open and closed position; said'closing solenoid being operatively connected to said operating arm, said closing solenoid being constructed to move said operating arm to said closed position responsive to energization of said closing solenoid; said latch member having a release position and a latching position, said latch being constructed to latch said operating arm in said closed position when said operating arm is moved to said closed position; said biasing means being constructed to bias said operating arm to said open position when said latch member is in said release position; said voltage measuring network comprising an electromagnetic motor having a core having an energizing winding wound thereon and a pivoted armature; said energizing winding being energized by the voltage of said supply circuit, the angular position of said pivoted armature being determined by the energization of said energizing winding; a pivoted contact assembly and an extension on said pivoted armature; said extension being constructed to carry contacts for cooperation with said pivoted contact assembly; said extension being moved into engagement with said pivoted contact assembly responsive to rotation of said pivoted armature due to a predetermined voltage value of said supply circuit, said auxiliary relay being energized responsive to contact engagement between said pivoted contact assembly and said extension; said solenoid being energized responsive to energization of said auxiliary relay; said latch member being operatively connected to said pivoted armature, rotation of said pivoted armature in a direction to disengage said extension and said pivoted contact assembly being eifective to move said latch member to said release position; means for supporting said pivoted armature and said pivoted contact assembly about a common pivoted axis, vibrational force and shock force being directionally effective in the same direction on both sides of said pivotal axis to thereby prevent development of a mechanical force couple in a direction to rotate said pivoted armature; said auxiliary latch being positioned to maintain said operating arm in said open position against shock, said auxiliary latch being constructed to unlatch said operating arm responsive to energization of said auxiliary relay; contact pressure springs; said contact springs being positioned to bias said pivoted contact assembly into electrical engagement with said contacts carried by said extension of said pivoted armature, calibration of said contact pressure springs being effective to adjust the drop out value of said direct current voltage; said common pivoted axis for said pivoted armature and said pivoted contact assembly insuring no wipe between contacts carried by said pivoted armature and contacts carried by said pivoted contact assembly to thereby avoid wiping friction and improve sensitivity.

6. A direct current voltage relay for measuring and responding to the voltage of a supply circuit and comprising main switch contacts, an operating arm, a biasing means, a closing solenoid, a latch member, a voltage measuring network, an auxiliary latch and an auxiliary relay; said operating arm being operatively connected to said switch contacts and constructed to be operable between an open and closed position; said closing solenoid being operatively connected to said operating arm, said closing solenoid being constructed to move said operating arm to said closed position responsive to energization of said closing solenoid; said latch member having a release position and a latching position, said latch being constructed to latch said operating arm in said closed osition when said operating arm is moved to said closed position; said biasing means being constructed to bias said operating arm to said open position when said latch member is in said release position; said voltage measuring network comprising an electromagnetic motor having a core having an energizing winding wound thereon and pivoted armature; said energizing winding being energized by the voltage of said supply circuit, the angular position of said pivoted armature being detern ed by the energization of said energizing winding; a pivoted contact assembly and an extension on said pivoted armature; said extension being constructed to carry contacts for cooperation with said pivoted contact assembly; said extension being moved into engagement with said pivoted contact assembly responsive to rotation of said pivoted armature due to a predetermined voltage value of said supply circuit, said auxiliary relay being energized responsive to contact engagement between said pivoted contact assembly and said extension; said closing solenoid being operatively connected to said operating arm, said closing solenoid being constructed to move said operating arm to said closed position responsive to energization of said closing solenoid; said latch member being operatively connected to said pivoted armature, rotation of said pivoted armature in a direction to disengage said extension and said pivoted contact assembly being eifective to move said latch member to said release position; means for supporting said pivoted armature and said pivoted contact assembly about a common pivoted axis, vibrational force and shock fore-c being directionally efiective in the same di ection on both sides of said pivotal axis to thereby prevent development of a mechanical force couple in a direction to rotate said pivoted armature; said auxiliary latch being po ioned to maintain said operating arm in said open position against shock, said auxiliary latch being constructed to unlatch said operating arm responsive to energization of said auxiliary relay; contact pressure springs; said contact springs being positioned to bias said pivoted contact assembly into electrical engagement with said contacts carried by said extension of said pivoted armature, calibration of said contact pressure springs being effective to adjust the drop out value of said direct current voltage relay.

7. A direct current voltage relay for measuring and responding to the voltage of a supply circuit and comprising main switch contacts, an operating arm, a biasing means, a closing solenoid, a latch member and a voltage measuring network, said operating arm being operatively connected to said switch contacts and cons ructe' to be operable between an open and closed position; said closing solenoid being operatively connected to said oper arm, said closing solenoid being constructed to nicvc said operating arm to said closed position responsive to energization of said closing solenoid; said latch member having a release position and a latching position, said latch being constructed to latch said operating arm in said closed post ion when said operating arm is moved to said closed position; said biasing means being constructed to bias said operating arm to said open position when said latch member is in said release position; said voltage incasui 3 network comprising an electromagnetic motor ha ng a core having an energizing Winding wound thereon and a pivoted armature; said energizing winding being ene ed by the voltage of said supply circuit, the angular position of said pivoted armature being determined by the cnergization of said energizing winding; a pivoted contact assembly and an extension on said pivoted armature; sion being constructed to carry contacts for cooperation with said pivoted contact assembly; said extension being moved into engagement with said pivoted contact assembly responsive to rotation of said pivoted armature due to a predetermined voltage value of said supply circuit, said solenoid being energized responsive contact engsge ment between said pivoted contact assembly an: cxtension; said latch member being opcratively connected to said pivoted armature, rotation of said pivoted annature in a direction to disengage said extension and said pivoted contact assembly being effective to sail latch member to said release position; means for supporting said pivoted armature and said pivoted con t assembly about a common pivoted axis, vibrational crcc and shock force being directionally effective in the same direction on both sides of said pivoted axis to thereby prevent development of a mechanical force cou in a direction to rotate said pivoted armature; contact prcssure springs; said contact springs being positioned to bias said pivoted contact assembly with electrical c mc with said contacts carried by said extension of 5 1d pivoted armature, calibration of said contact pressure springs being effective to adjust the drop out value of said direct current voltage relay.

8. A direct current voltage relay for measuring and responding to the voltage of a supply circuit and comprising main switch contacts, an operating arm, a biasing means, a closing solenoid, a latch member and a voltage measuring network, said operating arm being operatively connected to said switch contacts and constructed to be operable between an open and closed position; said closing solenoid being operatively connected to said operating arm, said closing solenoid being constructed to move said operating arm to said closed position responsive to energization of said closing solenoid; said latch member having a release position and a latching position, said latch being constructed to latch said operating arm in said closed position when said operating arm is moved to said closed position; said biasing means being constructed to bias said operating arm to said open position when said latch memher is in said release position; said voltage measuring network comprising an electroma netic motor having a core having an energizing winding wound thereon and a pivoted armature; said energizing being energized by the voltage of said supply circuit, the angular position of said pivoted armature being determined by the energization of said energizing winding; a pivoted contact assembly and an extension on said pivoted armature; said extension being constructed to carry contacts for cooperation with said pivoted contact assembly; said extension being moved into engagement with said pivoted contact assembly responsive to rotation of said pivoted armature due to a predetermined voltage value of said supply circuit, said solenoid being energized responsive to contact engagement between said pivoted contact assembly and said extension; said latch member being operatively connected to said pivoted armature, rotation of said pivoted armature in a direction to disengage said extension and said pivoted contact assembly being elfective to move said latch member to said release position; means for supporting said pivoted armature and said pivoted contact assembly about a common pivoted axis, vibrational force and shock force being directionally eifective in the same direction on both sides of said pivoted axis to thereby prevent development of a mechanical force couple in a direction to rotate said pivoted armature; said common pivoted axis for said pivoted armature and said pivoted contact assembly insuring no wipe between contacts carried by said pivoted armature and contacts carried by said pivoted contact assembly to thereby avoid wiping friction and improve sensitivity; contact pressure springs; said contact springs being positioned to bias said pivoted contact assembly into electrical engagement with said contacts carried by said extension of said pivoted armature, calibration of said contact pressure springs being efiective to adjust the drop out value of said direct .current voltage relay. I

9. A direct current voltage relay for measuring and responding to the voltage of a supply circuit and comprising main switch contacts, an operating arm, a biasing means, a closing solenoid, a latch member and a voltage measuring network, said operating arm being operatively connected to said switch contacts and constructed to be operable between an open and closed position; said closing solenoid being operatively connected to said operating arm, said closing solenoid being constructed to move said operating armto said closed position responsive to energization of said closing solenoid; said latch member having a release position and a latching position, said latch being constructed to latch said operating arm in said closed position when said operating arm is moved to said closed position; said biasing means being constructed to bias said operating arm to said open position when said latch member is in said release position; said voltage measuring network comprising an electromagnetic motor having a core having an energizing winding wound theron and a pivoted armature; said energizing winding being energized by the voltage of said supply circuit, the angular position of said pivoted armature being determined by the energization of said energizing winding; a pivoted contact assembly and an extension on said pivoted armature; said extension being constructed to carry contacts for cooperation with said pivoted contact assembly; said extension being moved into engagement with said pivoted contact assembly responsive to rotation of said pivoted armature due to a predetermined voltage value of said supply circuit, said solenoid being energized responsive to contact engagement between said pivoted contact assembly and said extension; said latch member being operatively connected to said pivoted armature, rotation of said pivoted armature in a direction to disengage said extension and said pivoted contact assembly being eifective to move said latch member to said release position; means for supporting said pivoted armature and said pivoted contact assembly about a common pivoted axis, vibrational force and shock force being directionally effective in the same direction on both sides of said pivoted axis to thereby prevent development of a mechanical force couple in a direction to rotate said pivoted armature; a shock counterbalanced means for said latch member; said shock counterbalanced means comprising a movable mass operatively connected to said latch member, shock energy impinged on said latch member being transmitted to said movable mass, said movable mass being moved to dissipate said shock energy.

10. A direct current voltage relay for measuring and responding to the voltage of a supply circuit and comprising main switch contacts, an operating arm, a biasing 14 means, a closing solenoid, a latch member, a voltage measuring network, an auxiliary latch and an auxiliary relay; said operating arm being operatively connected to said switch contacts and constructed to be operable between an open and closed position; said closing solenoid being operatively connected to said operating arm, said closing solenoid being constructed to move said operating arm to said closed position responsive to energization of said closing solenoid; said latch member having a release position and a latching position, said latch being constructed to latch said operating arm in said closed position when said operating arm is moved to said closed position; said biasing means being constructed to bias said operating arm to said open position when said latch member is in said release position; said voltage measuring network comprising an electromagnetic motor having a core having an energizing winding wound thereon and a pivoted armature; said energizing winding being energized by the voltage of said supply circuit, the angular position of said pivoted armature being determined by the energization of said energizing winding; a pivoted contact assembly and an extension on said pivoted armature; said extension being constructed to carry contacts for cooperation with said pivoted contact assembly; said extension being moved into engagement with said pivoted contact assembly responsive to rotation of said pivoted armature due to a predetermined voltage value of said supply circuit, said auxiliary relay being energized responsive to contact engagement between said pivoted contact assembly and said extension; said solenoid being energized responsive to energization of said auxiliary relay; said latch member being operatively connected to said pivoted armature, rotation of said pivoted armature in a direction to disengage said extension and said pivoted contact assembly being effective to move said latch member to said release position; means for supporting said pivoted armature and said pivoted contact assembly about a common pivoted axis, vibrational force and shock force being directionally effective in the same direction on both sides of said pivotal axis to thereby prevent development of a mechanical force couple in a direction to rotate said pivoted armature; said auxiliary latch being positioned to maintain said operating arm in said open position against shock, said auxiliary latch being constructed to unlatch said operating arm responsive to energization of said auxiliary relay; a shock counterbalanced means for said latch member; said shock counterbalanced means comprising a movable mass operatively connected to said latch member, shock energy impinged on said latch member being transmitted to said movable mass, said movable mass being moved to dissipate said shock energy.

11. A direct current voltage relay for measuring and responding to the voltage of a supply circuit and comprising main switch contacts, an operating arm, a biasing means, a closing solenoid, a latch member and a voltage measuring network, said operating arm being operatively connected to said switch contacts and constructed to be operable between an open and closed position; said closing solenoid being operatively connected to said operating arm, said closing solenoid being constructed to move said operating arm to said closed position responsive to energization of said closing solenoid; said latch member having a release position and a latching position, said latch being constructed to latch said operating arm in said closed position when said operating arm is moved to said closed position; said biasing means being constructed to bias said operating arm to said open position when said latch member is in said release position; said voltage measuring network comprising an electromagnetic motor having a core having an energizing winding wound thereon and a pivoted armature; said energizing winding being energized by the voltage of said supply circuit, the angular position of said pivoted armature being determined by the energization of said energizing winding; a pivoted contact assembly and an extension on said pivoted armature; said extension being constructed to carry contacts for cooperation with said pivoted contact assembly; said extension being moved into engagement with said pivoted contact assembly responsive to rotation of said pivoted armature due to a predetermined voltage value of said supply circuit, said solenoid being energized responsive to contact engagement between said pivoted contact assembly and said extension; said latch member being operatively connected to'said pivoted armature; said operative connection between said latch member and said pivoted armature constructed to have free play; rotation of said pivoted armature in a direction to disengage said extension and said pivoted contact assembly being efiective to move said latch member to said release position; after said free play is taken up to thereby move said latch member with a snap action; means for supporting said pivoted armature and said pivoted contact assembly about a common pivoted axis, vibrational force and shock force being directionally effective in the same direction on both sides of said pivoted axis to thereby prevent development of a mechanical force couple in a direction to rotate said pivoted armature.

12. A direct current voltage relay for measuring and responding to the voltage of a supply circuit and comprising main switch contacts, an operating arm, a biasing means, a closing solenoid, a latch member, a voltage measuring network, an auxiliary latch and an auxiliary relay; said operating arm being operatively connected to said switch contacts and constructed to be operable between an open and closed position; said closing solenoid being operatively connected to said operating arm, said closing solenoid being constructed to move said operatingarm to said closed position responsive to energization of said closing solenoid; said latch member having a release position and a latching position, said latch being constructed to latch said operating arm in said closed position when said operating arm is moved to said closed position; said biasing means being constructed to bias said operating arm to said open position when said latch member is in said release position; said voltage measuring network comprising an electromagnetic motor having a core having an energizing winding wound thereon and a pivoted armature; said energizing winding being energized by the voltage of said supply circuit, the angular position 'of said pivoted armature being determined by the energization of said energizing winding; a pivoted contactassembly and an extension on said pivoted armaa ture; said extension being constructed to carry contacts for cooperation with said pivoted contact assembly; said extension being moved into engagement with said pivoted contact assembly responsive to rotation of said pivoted armature due to a predetermined voltage value of said supply circuit, said auxiliary relay being energized responsive to contact engagement between said pivoted contact assembly and said extension; said solenoid being energized responsive to energization of said auxiliary relay; said latch member being operatively connected to said pivoted armature; said operative connection between said latch member and said pivoted armature constructed to have free play; rotation of said pivoted armature in a direction to disengage said extension and said pivoted contact assembly being effective to move said latch member to said release position; after said free play is taken up to thereby move said latch member with a snap action; meansafor supporting said pivoted armature and said pivoted contact assembly about a common pivoted axis, vibrational force and shock force being directionally effective in the same direction on both sides of said pivotal axis to thereby prevent development of a mechanical force couple in a direction to rotate said pivoted armature; said auxiliary latch being positioned to maintain said operating arm in said open position against shock, said auxiliary latch being constructed to unlatch said operating arm responsive to energization of said auxiliary relay.-

References Cited in the file of this patent UNITED STATES PATENTS 1,548,800 Hilliard Aug. 4, 1925 2,225,055 Hoye Dec. 17, 1940 2,422,861 Skrobisch June 24, 1947 2,482,524 Vrooman Sept. 20, 1949 2,519,293 Schaelchlin Aug. 15, 1950 2,540,294 Schleicher Feb. 6, ll 

